Synbiotic mixture

ABSTRACT

This invention relates to a preparation comprising N-acetyl-lactosamine and/or an oligosaccharide containing N-acetyl-lactosamine and a probiotic  Lactobacillus  sp. The invention extends to nutritional compositions comprising said preparation and to the use of the preparation in the prevention and treatment of pathogenic infections of the gastro-intestinal and upper respiratory tracts.

FIELD OF THE INVENTION

This invention relates to a preparation comprising a probiotic and aprebiotic oligosaccharide which is specifically designed to enhance theefficacy of the probiotic, to food products comprising said preparationand to uses of the preparation.

BACKGROUND OF THE INVENTION

Mother's milk is recommended for all infants. However, in some casesbreast feeding is inadequate or unsuccessful for medical reasons or themother chooses not to breast feed. Infant formulas have been developedfor these situations.

In the recent past, certain strains of bacteria have attractedconsiderable attention because they have been found to exhibit valuableproperties for man if ingested. In particular, specific strains of thegenera Lactobacilli and Bifidobacteria have been found to be able tocolonise the intestinal mucosa, to reduce the capability of pathogenicbacteria to adhere to the intestinal epithelium, to haveimmunomodulatory effects and to assist in the maintenance of well-being.Such bacteria are sometimes called probiotics and it has already beenproposed to add suitable probiotic bacteria to infant formulas.

Extensive studies have been carried out to identify new probioticstrains. For example, EP 0 199 535, EP 0 768 375, WO 97/00078, EP 0 577903 and WO 00/53200 disclose specific strains of Lactobacilli andBifidobacteria and their beneficial effects.

As indicated above, by reason of their abilities to colonise theintestinal mucosa and reduce the capacity of pathogenic bacteria toadhere to the intestinal epithelium, certain probiotic strains havealready been proposed for the prevention and treatment of diarrhoea ininfants. For example, Lactobacillus rhamnosus ATCC 53103 which is soldinter alia by Valio Oy of Finland under the trade mark LGG has beenreported to be effective in reducing bacterially-induced diarrhoea ininfants and young children (Canani et al, British Medical Journal 2007,Aug. 18; 335 (7615):340). commonly added to human foods, such asfermented milk products.

Another approach to preventing or treating infection of thegastrointestinal tract with bacterial pathogens such as Escherichia coli(EPEC) is the administration of prebiotics, for example by addition tofoodstuffs. A prebiotic is a non-digestible food ingredient thatbeneficially affects the host by selectively stimulating the growthand/or activity of one or a limited number of bacteria in the colon, andthus improves host health. Such ingredients are non-digestible in thesense that they are not broken down and absorbed in the stomach or smallintestine and thus pass intact to the colon where they are selectivelyfermented by the beneficial bacteria. Examples of prebiotics includecertain oligosaccharides, such as fructooligosaccharides (FOS) andgalactooligosaccharides (GOS). Shoaf et al investigated the ability ofvarious prebiotics including fructooligosaccharides, inulin,galacto-oligosaccharides, lactulose and raffinose to inhibit theattachment of EPEC strain E2348/69 on Hep-2 and Caco-2 cells. Theyobserved that purified galacto-oligosaccharides exhibited the greatestadherence inhibition on both HEp-2 and Caco-2 cells, reducing theadherence of EPEC by 65 and 70%, respectively and concluded that theirobservations suggested that some prebiotic oligosaccharides may haveanti-adhesive activity and directly inhibit the adherence of pathogensto the host epithelial cell surface (Infect Immun 2006 December; 74(12): 6920-8).

Human milk is known to contain a larger amount of indigestibleoligosaccharides than most other animal milks. In fact, indigestibleoligosaccharides represent the third largest solid component (afterlactose and lipids) in breast milk, occurring at a concentration of12-15 g/l in colostrum and 5-8 g/l in mature milk. Human milkoligosaccharides are very resistant to enzymatic hydrolysis, indicatingthat these oligosaccharides may display essential functions not directlyrelated to their calorific value.

As the composition of human milk becomes better understood, it has alsobeen proposed to add prebiotics to infant formula. Various infantformulas supplemented with prebiotics such as mixtures offructooligosaccharides and galactooligosaccharides for example arecommercially available. However, such mixtures approximate only roughlythe mixture of oligosaccharides in human milk. Over 100 differentoligosaccharide components have been detected in human milk some ofwhich have not been so far detected in animal milks such as bovine milkat all or have been detected only in small quantities. Examples ofclasses of human milk oligosaccharide that are present in bovine milkand colostrum only in very small quantities or not at all are sialylatedand fucosylated oligosaccharides.

The number and function of these various oligosaccharides are stillbeing elucidated although certain of them have also been associated withreducing the ability of pathogens to adhere to host epithelial cells.For example, Cravioto et al reported that an oligosaccharide-enrichedfraction from human milk inhibited the attachment of EPEC to HEp-2 cells(The Journal of Infectious Diseases 1991; 163:1247-1255).

Infant formulas containing both probiotics and prebiotics have also beenproposed in the continual quest to produce infant formulas whichreplicate as closely as possible the composition and efficacy of humanmilk. For example, in WO 2007/101675 it is proposed to supplement infantformula with a mixture of a probiotic bacterial strain and a mixture ofN-acetylated, neutral and sialylated oligosaccharides which mixtureprovides a closer approximation to the oligosaccharides in human milkthan does the commercially available mixtures of fructo- andgalacto-oligosaccharides described above. It is stated that thismixture, which is described as a symbiotic, is useful for the preventionof pathogenic infections.

However, there is a continuing need to still further improve theprotective effects of infant formulas and the like compositions bycombining specific probiotics and prebiotics with particularlybeneficial effects.

SUMMARY OF THE INVENTION

It has now surprisingly been found that administration ofN-acetyl-lactosamine and/or oligosaccharides containingN-acetyl-lactosamine is highly efficacious in enhancing the beneficialeffects and efficiency of probiotic Lactobacillus sp co-administeredwith the oligosaccharide.

Accordingly, in a first aspect, the present invention provides apreparation comprising N-acetyl-lactosamine and/or an oligosaccharidecontaining N-acetyl-lactosamine and a probiotic Lactobacillus sp.

In a second aspect, the present invention provides the use of aprobiotic Lactobacillus sp and N-acetyl-lactosamine and/or anoligosaccharide containing N-acetyl-lactosamine in the manufacture of amedicament or nutritional composition for the prevention and/ortreatment of pathogenic infections of the gastro-intestinal or upperrespiratory tract.

The invention extends to a method for the prevention or treatment ofpathogenic infections of the gastro-intestinal or upper respiratorytract in a subject in need thereof which comprises administering to thesubject a therapeutic amount of a preparation comprising a probioticbacterial strain and a probiotic Lactobacillus sp andN-acetyl-lactosamine and/or an oligosaccharide containingN-acetyl-lactosamine.

The present inventors have previously demonstrated that a mixture ofN-acetylated, neutral and sialylated oligosaccharides obtained fromcows' milk is effective to stimulate Lactobacillus rhamnosus CGMCC1.3724 to alleviate bacterial toxin induced damage and that the observedprotection depends on bacterial-host cell crosstalk which is mediated inthe presence of the OS blend (unpublished data). Without wishing to bebound by theory, the present inventors believe that the effectiveness ofa combination of N-acetyl-lactosamine and/or an oligosaccharidecontaining N-acetyl-lactosamine with a probiotic Lactobacillus in theprevention or treatment of pathogenic infections of the upperrespiratory and gastrointestinal tracts is due to a synergisticreduction in the ability of the pathogen to adhere to the luminalepithelium by the direct effect of the oligosaccharide on the bundleforming pili adhesins and other adhesins (e.g. intimin) and the indirecteffect of the stimulated host-probiotic Lactobacillus crosstalk.

DETAILED DESCRIPTION OF THE INVENTION

In the present specification, the following words are given a definitionthat must be taken into account when reading and interpreting thedescription, examples and claims:

“infant” means a child under the age of 12 months;

“infant formula” means a foodstuff intended for the complete nutritionof infants during the first four to six months of life and as acomplement to other foodstuffs up to the age of 12 months;

“probiotic bacteria” means microbial cell preparations or components ofmicrobial cells with a beneficial effect on the health or well-being ofthe host. (Salminen S, Ouwehand A. Benno Y. et al “Probiotics: howshould they be defined” Trend Food Sci. Technol. 1999:10 107-10);

The invention relates to N-acetyl-lactosamine and/or an oligosaccharidecontaining N-acetyl-lactosamine. Suitable oligosaccharides containingN-acetyl-lactosamine include lacto-N-tetraose (LNT) andlacto-N-neotetraose (LNnT). LNT and LNnT may be synthesised chemicallyby enzymatic transfer of saccharide units from donor moieties toacceptor moieties using glycosyltransferases as described for example inU.S. Pat. No. 5,288,637. Alternatively, LNT and LNnT may be prepared bychemical conversion of keto-hexoses (e.g. fructose) either free or boundto an oligosaccharide (e.g. lactulose) into N-acetylhexosamine or anN-acetylhexosamine containing oligosaccharide as described in Wrodnigg,T. M.; Stutz, A. E. (1999) Angew. Chem. Int. Ed. 38:827-828.N-acetyllactosamine produced in this way may then be transferred tolactose as acceptor moiety.

The probiotic Lactobacillus may be selected from any Lactobacillusstrain which satisfies the definition of a probiotic and has acceptableshelf-life for the product into which the preparation of the inventionis to be incorporated. For example, infant formulas are required toremain stable and effective for up to 36 months. Of course, thepreparation of the invention does not need to be incorporated intoanother product such as a foodstuff but may be ingested as is or mixedwith a suitable excipient in the form of a powder or capsule orcompressed into tablets for example.

Examples of preferred Lactobacillus species are Lactobacillus rhamnosus,Lactobacillus paracasei and Lactobacillus reuteri. Particularlypreferred strains are Lactobacillus rhamnosus ATCC 53103, Lactobacillusrhamnosus CGMCC 1.3724, Lactobacillus paracasei CNCM 1-2116,Lactobacillus reuteri ATCC 55730 and Lactobacillus reuteri DSM 17938.

The selected probiotic Lactobacillus may be cultured according to anysuitable method known in the art and prepared for addition to thepreparation or nutritional composition of the invention by freeze-dryingor spray-drying for example. Alternatively, bacterial strains can bebought from specialist suppliers such as Christian Hansen and Morinagaalready prepared in a suitable form for addition to nutritionalcompositions such as infant formula.

The preparation of the invention may provide between 10² and 10¹⁰ cfu ofprobiotic bacteria for each gram of the oligosaccharide.

In a preferred aspect of the invention, the preparation described aboveis incorporated into a nutritional composition. In the context of thepresent invention, the term “nutritional composition” is intended toencompass any consumable matter. Hence, it may be a product intended forconsumption by humans, in particular infant formula, growing up milk,and the like. However, consumption of the preparation is not restrictedto infants and children In particular, the preparation of the inventioncan be incorporated into dehydrated milk or cereal mixtures.

The food product can comprise 0.3 to 4% by weight of the N-acetyllactosamine and/or an oligosaccharide containing N-acetyl lactosamine.The oligosaccharide containing the N-acetyl lactosamine can belacto-N-tetraose or lacto-N-neotetraose.

The nutritional composition is preferably an infant formula whichcontains N-acetyl-lactosamine and/or an oligosaccharide containingN-acetyl-lactosamine in an amount between 0.1 and 3 g/100 g compositionon a dry weight basis.

An infant formula according to the present invention may contain aprotein source in an amount of not more than 2.0 g/100 kcal, preferably1.8 to 2.0 g/100 kcal. The type of protein is not believed to becritical to the present invention provided that the minimum requirementsfor essential amino acid content are met and satisfactory growth isensured although it is preferred that over 50% by weight of the proteinsource is whey. Thus, protein sources based on whey, casein and mixturesthereof may be used as well as protein sources based on soy. As far aswhey proteins are concerned, the protein source may be based on acidwhey or sweet whey or mixtures thereof and may include alpha-lactalbuminand beta-lactoglobulin in whatever proportions are desired.

The proteins may be intact or hydrolysed or a mixture of intact andhydrolysed proteins. It may be desirable to supply partially hydrolysedproteins (degree of hydrolysis between 2 and 20%), for example forinfants believed to be at risk of developing cows' milk allergy. Ifhydrolysed proteins are required, the hydrolysis process may be carriedout as desired and as is known in the art. For example, a whey proteinhydrolysate may be prepared by enzymatically hydrolysing the wheyfraction in one or more steps. If the whey fraction used as the startingmaterial is substantially lactose free, it is found that the proteinsuffers much less lysine blockage during the hydrolysis process. Thisenables the extent of lysine blockage to be reduced from about 15% byweight of total lysine to less than about 10% by weight of lysine; forexample about 7% by weight of lysine which greatly improves thenutritional quality of the protein source.

The infant formula may contain a carbohydrate source. Any carbohydratesource conventionally found in infant formulae such as lactose,saccharose, maltodextrin, starch and mixtures thereof may be usedalthough the preferred source of carbohydrates is lactose. Preferablythe carbohydrate sources contribute between 35 and 65% of the totalenergy of the formula.

The infant formula may contain a source of lipids. The lipid source maybe any lipid or fat which is suitable for use in infant formulas.Preferred fat sources include palm olein, high oleic sunflower oil andhigh oleic safflower oil. The essential fatty acids linoleic andα-linolenic acid may also be added as may small amounts of oilscontaining high quantities of preformed arachidonic acid anddocosahexaenoic acid such as fish oils or microbial oils. In total, thefat content is preferably such as to contribute between 30 to 55% of thetotal energy of the formula. The fat source preferably has a ratio ofn-6 to n-3 fatty acids of about 5:1 to about 15:1; for example about 8:1to about 10:1.

The infant formula may also contain all vitamins and minerals understoodto be essential in the daily diet and in nutritionally significantamounts. Minimum requirements have been established for certain vitaminsand minerals. Examples of minerals, vitamins and other nutrientsoptionally present in the infant formula include vitamin A, vitamin B1,vitamin B2, vitamin B6, vitamin B12, vitamin E, vitamin K, vitamin C,vitamin D, folic acid, inositol, niacin, biotin, pantothenic acid,choline, calcium, phosphorous, iodine, iron, magnesium, copper, zinc,manganese, chloride, potassium, sodium, selenium, chromium, molybdenum,taurine, and L-carnitine. Minerals are usually added in salt form. Thepresence and amounts of specific minerals and other vitamins will varydepending on the intended infant population.

If necessary, the infant formula may contain emulsifiers and stabiliserssuch as soy lecithin, citric acid esters of mono- and di-glycerides, andthe like.

In addition to the N-acetyl-lactosamine and/or an oligosaccharidecontaining N-acetyl-lactosamine the infant formula preferably furthercontains at least one prebiotic in an amount of 0.3 to 10%. A prebioticis a non-digestible food ingredient that beneficially affects the hostby selectively stimulating the growth and/or activity of one or alimited number of bacteria in the colon, and thus improves host health.Such ingredients are non-digestible in the sense that they are notbroken down and absorbed in the stomach or small intestine and thus passintact to the colon where they are selectively fermented by thebeneficial bacteria. Examples of prebiotics include certainoligosaccharides, such as fructooligosaccharides (FOS) andgalactooligosaccharides (GOS). A combination of prebiotics may be usedsuch as 90% GOS with 10% short chain fructo-oligosaccharides such as theproduct sold under the trade mark Raftilose® or 10% inulin such as theproduct sold under the trade mark Raftiline®. A particularly preferredcombination of prebiotics is a mixture comprising 5-70 wt % of at leastone N-acetylated oligosaccharide selected from the group comprisingGalNAcα-1,3Galβ1,4Glc and Galβ1,6GalNAcα1,3Galβ1,4Glc, 20-95 wt % of atleast one neutral oligosaccharide selected from the group comprisingGalβ1,6Gal, Galβ1,6Galβ1,4Glc Galβ1,6Galβ1,6Glc, Galβ1,3Galβ1,3Glc,Galβ1,3Galβ1,4Glc, Galβ1,6Galβ1,6Galβ1,4Glc, Galβ1,6Galβ1,3Galβ1,4GlcGalβ1,3Galβ1,6Galβ1,4Glc and Galβ1,3Galβ1,3Galβ1,4Glc and 2-50 wt % ofat least one sialylated oligosaccharide selected from the groupcomprising NeuAcα-2,3Galβ1,4Glc and NeuAcα-2,6Galβ1,4Glc. Such a mixturemay be prepared from an animal milk as described for example inWO2007/101675.

The infant formula may optionally contain other substances which mayhave a beneficial effect such as lactoferrin, nucleotides, nucleosides,and the like.

If the preparation of the invention is to be incorporated in an infantformula or other milk-based nutritional composition, the composition maybe prepared in any suitable manner known in the art. For example, aninfant formula may be prepared by blending together the protein source,any carbohydrates other than lactose and the fat source in appropriateproportions. Emulsifiers may be added if desired. Vitamins and mineralsmay be added at this point but are usually added later to avoid thermaldegradation. Any lipophilic vitamins, emulsifiers and the like may bedissolved into the fat source prior to blending. Water, preferably waterwhich has been subjected to reverse osmosis, may then be mixed in toform a liquid mixture.

The liquid mixture may then be thermally treated to reduce bacterialloads. For example, the liquid mixture may be rapidly heated to atemperature in the range of about 80° C. to about 110° C. for about 5seconds to about 5 minutes. This may be carried out by steam injectionor by heat exchanger, e.g. a plate heat exchanger.

The liquid mixture may then be cooled to about 60° C. to about 85° C.,for example by flash cooling. The liquid mixture may then behomogenised, for example in two stages at about 7 MPa to about 40 MPa inthe first stage and about 2 MPa to about 14 MPa in the second stage. Thehomogenised mixture may then be further cooled to add any heat sensitivecomponents such as vitamins and minerals. The pH and solids content ofthe homogenised mixture is conveniently standardised at this point.

The homogenised mixture is transferred to a suitable drying apparatus,such as a spray drier or freeze drier, and converted to powder. Thepowder should have a moisture content of less than about 5% by weight.

The preparation of the invention may be made up in advance and addeddirectly to nutritional composition by dry mixing. Alternatively, theprobiotic Lactobacillus and the N-acetyl-lactosamine and/oroligosaccharide containing N-acetyl-lactosamine may be added separatelyto the nutritional composition by dry mixing.

In another embodiment, the preparation of the invention may be in theform of a supplement including the probiotic Lactobacillus and theN-acetyl-lactosamine and/or an oligosaccharide containingN-acetyl-lactosamine in an amount sufficient to achieve the desiredeffect in an individual. Preferably the daily dose of theN-acetyl-lactosamine and/or oligosaccharide containingN-acetyl-lactosamine is from 0.1 to 3 g and the daily dose of theprobiotic Lactobacillus is from 10e5 to 10e12 cfu. The amounts ofN-acetyl-lactosamine and/or oligosaccharide containingN-acetyl-lactosamine and probiotic Lactobacillus to be included in thesupplement will be selected accordingly depending upon how thesupplement is to be administered. For example, if the supplement is tobe administered twice a day, each supplement may contain 0.05 to 1.5 gN-acetyl-lactosamine and/or oligosaccharide containingN-acetyl-lactosamine and 10e3 to 10e6 cfu of probiotic Lactobacillus.The supplement may be in the form of tablets, capsules, pastilles or aliquid for example. The supplement may further contain protectivehydrocolloids (such as gums, proteins, modified starches), binders, filmforming agents, encapsulating agents/materials, wall/shell materials,matrix compounds, coatings, emulsifiers, surface active agents,solubilizing agents (oils, fats, waxes, lecithins etc.), adsorbents,carriers, fillers, co-compounds, dispersing agents, wetting agents,processing aids (solvents), flowing agents, taste masking agents,weighting agents, jellifying agents and gel forming agents. Thesupplement may also contain conventional pharmaceutical additives andadjuvants, excipients and diluents, including, but not limited to,water, gelatine of any origin, vegetable gums, ligninsulfonate, talc,sugars, starch, gum arabic, vegetable oils, polyalkylene glycols,flavouring agents, preservatives, stabilizers, emulsifying agents,buffers, lubricants, colorants, wetting agents, fillers, and the like.

Further, the supplement may contain an organic or inorganic carriermaterial suitable for oral or enteral administration as well asvitamins, minerals trace elements and other micronutrients in accordancewith the recommendations of Government bodies such as the USRDA.

A preparation according to the invention may be effective in theprevention and treatment of both bacterial and viral pathogenicinfections of the upper respiratory and gastrointestinal tractsincluding by rotaviruses and noroviruses, enteropathogenic E. coli(EPEC), enterohaemorhagic E. coli (EHEC) enterotoxigenic E. coli (ETEC)and Salmonella sp as regards infections of the gastrointestinal tractand by respiratory syncytial virus, bocaviruses and rhinoviruses,Streptococcus pneumoniae, Haemophilus influenzae and Moraxellacatarrhalis as regards infections of the upper respiratory tract. Apreparation according to the invention may be particularly effective inthe prevention and treatment of otitis media, a condition which isassociated with frequent respiratory tract infections.

The invention will now be further illustrated by reference to thefollowing example.

Example 1

An example of the composition of a suitable infant formula to be used inthe present invention is given below

Nutrient per 100 kcal per litre Energy (kcal) 100 670 Protein (g) 1.8312.3 Fat (g) 5.3 35.7 Linoleic acid (g) 0.79 5.3 α-Linolenic acid (mg)101 675 Lactose (g) 11.2 74.7 Minerals (g) 0.37 2.5 Na (mg) 23 150 K(mg) 89 590 Cl (mg) 64 430 Ca (mg) 62 410 P (mg) 31 210 Mg (mg) 7 50 Mn(μg) 8 50 Se (μg) 2 13 Vitamin A (μg RE) 105 700 Vitamin D (μg) 1.5 10Vitamin E (mg TE) 0.8 5.4 Vitamin K1 (μg) 8 54 Vitamin C (mg) 10 67Vitamin B1 (mg) 0.07 0.47 Vitamin B2 (mg) 0.15 1.0 Niacin (mg) 1 6.7Vitamin B6 (mg) 0.075 0.50 Folic acid (μg) 9 60 Pantothenic acid (mg)0.45 3 Vitamin B12 (μg) 0.3 2 Biotin (μg) 2.2 15 Choline (mg) 10 67 Fe(mg) 1.2 8 I (μg) 15 100 Cu (mg) 0.06 0.4 Zn (mg) 0.75 5 LNnT (mg) 37250 L. rhamnosus CGMCC 2.10⁷ cfu/g of powder, 1.3724 live bacteria

The invention claimed is:
 1. A composition selected from the groupconsisting of an infant formula and a growing up milk for treatment ofpathogenic infections of a gastro-intestinal tract or an upperrespiratory tract, the composition comprising: lacto-N-neotetraose in anamount of 0.1 to 3% by dry weight of the composition; and a probioticLactobacillus sp selected from the group consisting of (i) Lactobacillusrhamnosus CGMCC 1.3724 in an amount between 10² and 10¹⁰ cfu for eachgram of the lacto-N-neotetraose and (ii) Lactobacillus reuteri DSM 17938in an amount between 10² and 10¹⁰ cfu for each gram of thelacto-N-neotetraose.
 2. The composition of claim 1 wherein the probioticLactobacillus sp is Lactobacillus rhamnosus CGMCC 1.3724.
 3. Thecomposition of claim 1 wherein the probiotic Lactobacillus sp isLactobacillus reuteri DSM
 17938. 4. The composition of claim 1 whereinthe lacto-N-neotetraose is the only oligosaccharide containingN-acetyl-lactosamine in the composition.
 5. A food product comprising0.3 to 4% by weight based on dry matter of a component for treatment ofpathogenic infections of a gastro-intestinal tract or an upperrespiratory tract, the component comprising lacto-N-neotetraose in anamount of 0.1 to 3% by dry weight of the food product and furthercomprising a probiotic Lactobacillus sp selected from the groupconsisting of Lactobacillus rhamnosus CGMCC 1.3724 and Lactobacillusreuteri DSM 17938.